As a solar battery module, a solar battery module having such a configuration that a plurality of solar battery cells having a light-receiving-surface bus electrode on a light receiving surface as a collective electrode and a rear-surface bus electrode on a rear surface are arranged in parallel in a matrix; a light-receiving-surface bus electrode of a certain solar battery cell is connected to a rear-surface bus electrode of another solar battery cell adjacent thereto by a belt-shaped lead wire (an interconnector); and this process is sequentially repeated to electrically connect a plurality of solar battery cells has been known.
The belt-shaped lead wire is generally referred to as “tab wire”, and a lead wire in which the whole surface of highly conductive metal is solder-coated, such as copper foil or metal foil is used. The lead wire is spanned and arranged from a light-receiving-surface electrode of one solar battery cell to a rear-surface electrode of an adjacent solar battery cell, and the light-receiving-surface electrode and the rear-surface electrode of the both cells are electrically connected.
The connection between the lead wire and the respective electrodes is performed by arranging the lead wire on the electrodes formed in a strip form on the surface and the rear surface of the solar battery cell, heating the lead wire to melt the solder, and, in this state, by pressing the lead wire to the solar battery cell partially or over the whole length to perform solder joining thereto.
In such lead wire joining of the solar battery cell, heating is performed by main heating by infrared rays irradiated from an infrared lamp heater, for example, arranged above the solar battery cell, and auxiliary heating from a hot plate on which the solar battery cell is placed, and pressing is performed by pressurizing the lead wire to the silicon substrate at a plurality of points away from each other in a length direction of the lead wire.
The lead wire is joined to the surface by melting the coated solder, or may be also joined thereto by pressing in a state with a resin applied to the surface of the solar battery cell or the lead wire being melted. The connection structure described above by solder or resin of the belt-shaped lead wire is disclosed in Patent Literature 1, for example.